CFD Online Discussion Forums - [Other] Pointwise Mesh into Fluent - Error: "Divergence detected in AMG solver: ads-0."

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Pointwise Mesh into Fluent - Error: "Divergence detected in AMG solver: ads-0."

I have been having trouble on initialization and get an error:
"Divergence detected in AMG solver: ads-0."

I have tried adjusting the relaxation factors, but it did not work. I have been on the forums many times looking for a solution and some say this error appears if you have a bad mesh quality.

I have been trying unsuccessfully for a few days to get an unstructured grid of a multi-element airfoil to pass a mesh check in ANSYS Fluent. When I check the mesh quality in Pointwise it says the grid has a good quality, but I get several errors in Fluent. Fluent output is printed like this when I check the mesh:

Code:

Warning: non-positive volumes exist.



   minimum volume (m3): -4.975500e-02

   maximum volume (m3): -1.800502e-07

     total volume (m3): -5.991529e+01

 Face area statistics:

   minimum face area (m2): 3.727322e-04

   maximum face area (m2): 4.325760e-01

 Checking mesh..........

WARNING: left-handed faces detected on zone   3:     0 right-handed, 130360 left-handed.

WARNING: left-handed faces detected on zone   4:     0 right-handed,    39 left-handed.

WARNING: left-handed faces detected on zone   5:     0 right-handed,    78 left-handed.

WARNING: left-handed faces detected on zone   6:     0 right-handed,    39 left-handed.

WARNING: left-handed faces detected on zone   7:     0 right-handed,  2782 left-handed..

   Zone   2: 263658 face(s) with wrong node order (on 1000000)..............

Done.



WARNING: Mesh check failed.



To get more detailed information about the mesh check failure

increase the mesh check verbosity via the TUI command

/mesh/check-verbosity.

Fluent can also try to fix the mesh check problems via the TUI command

/mesh/repair-improve/repair.

Any thoughts on how to repair this mesh? The "repair" command in the TUI did not work.
Thank you in advance for any help.

Kyle, hi!

Have you managed to solve the problem and how? I have the same problem.

Regards, Mark.

Hello Mark,

I was able to solve the problem, but to be honest this was several months ago now, and it is not really clear in my memory still. I do remember when I was getting errors I had several fields; structured around the airfoil, and unstructured far field. I was able to use existing wind tunnel data for the tested airfoil to validate a method of generation for a fully unstructured grid. This resulted in a single field which then was imported to fluent and passed all checks. However, I still used the TUI commands to further refine the mesh to achieve a higher grid quality in fluent after import. If you have any more questions regarding don't hesitate to ask, and maybe I can screenshot a few things I remember doing to help you out.

Regards,
Kyle

Hi, I managed to solve the problem, but I do not remember how either. I have a filling that I forgot to set "length" units to mm or something alike.

Regards, Mark.